System and method for traversing a nat device for peer-to-peer hybrid communications

ABSTRACT

An improved system and method are disclosed for peer-to-peer communications. In one example, the method enables an endpoint to traverse a NAT device using a stateless reflector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/494,958, filed on Jun. 30, 2009, which is a continuation of U.S.patent application Ser. No. 11/214,648, filed on Aug. 30, 2005, which isa continuation-in-part of U.S. patent application Ser. No. 11/081,068,filed on Mar. 15, 2005, which claims the benefit of U.S. ProvisionalPatent Ser. Nos. 60/583,536, filed Jun. 29, 2004, 60/628,183, filed Nov.15, 2004, and 60/628,291, filed Nov. 17, 2004, all of which are herebyincorporated by reference.

BACKGROUND

Current packet-based communication networks may be generally dividedinto peer-to-peer networks and client/server networks. Traditionalpeer-to-peer networks support direct communication between variousendpoints without the use of an intermediary device (e.g., a host orserver). Each endpoint may initiate requests directly to other endpointsand respond to requests from other endpoints using credential andaddress information stored on each endpoint. However, becausetraditional peer-to-peer networks include the distribution and storageof endpoint information (e.g., addresses and credentials) throughout thenetwork on the various insecure endpoints, such networks inherently havean increased security risk. While a client/server model addresses thesecurity problem inherent in the peer-to-peer model by localizing thestorage of credentials and address information on a server, adisadvantage of client/server networks is that the server may be unableto adequately support the number of clients that are attempting tocommunicate with it. As all communications (even between two clients)must pass through the server, the server can rapidly become a bottleneckin the system.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to thefollowing description taken in conjunction with the accompanyingDrawings in which:

FIG. 1 is a simplified network diagram of one embodiment of a hybridpeer-to-peer system.

FIG. 2 a illustrates one embodiment of an access server architecturethat may be used within the system of FIG. 1.

FIG. 2 b illustrates one embodiment of an endpoint architecture that maybe used within the system of FIG. 1.

FIG. 2 c illustrates one embodiment of components within the endpointarchitecture of FIG. 2 b that may be used for cellular networkconnectivity.

FIG. 2 d illustrates a traditional softswitch configuration with twoendpoints.

FIG. 2 e illustrates a traditional softswitch configuration with threeendpoints and a media bridge.

FIG. 2 f illustrates one embodiment of the present disclosure with twoendpoints, each of which includes a softswitch.

FIG. 2 g illustrates one embodiment of the present disclosure with threeendpoints, each of which includes a softswitch.

FIG. 3 a is a sequence diagram illustrating the interaction of variouscomponents of FIG. 2 b when placing a call.

FIG. 3 b is a sequence diagram illustrating the interaction of variouscomponents of FIG. 2 b when receiving a call.

FIG. 4 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may be authenticated and communicate with anotherendpoint.

FIG. 5 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may determine the status of another endpoint.

FIG. 6 is a sequence diagram illustrating an exemplary process by whichan access server of FIG. 1 may aid an endpoint in establishingcommunications with another endpoint.

FIG. 7 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may request that it be added to the buddy list ofanother endpoint that is currently online.

FIG. 8 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may request that it be added to the buddy list ofanother endpoint that is currently offline.

FIG. 9 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may request that it be added to the buddy list ofanother endpoint that is currently offline before it too goes offline.

FIG. 10 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may send a voicemail to another endpoint that isonline.

FIG. 11 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 1 may send a voicemail to another endpoint that isoffline.

FIG. 12 is a simplified diagram of another embodiment of a peer-to-peersystem that is coupled to destinations outside of the peer-to-peersystem.

FIG. 13 is a sequence diagram illustrating an exemplary process by whichan endpoint of FIG. 12 may directly contact a destination outside of thepeer-to-peer system.

FIG. 14 is a flowchart of one embodiment of a method by which a routingtable may be downloaded and utilized by an endpoint.

FIG. 15 is a sequence diagram illustrating an exemplary process by whichan external device may establish contact with an endpoint within thepeer-to-peer system of FIG. 12.

FIG. 16 is a flowchart of one embodiment of a method by which anendpoint may provide interactive voice response functionality.

FIG. 17 is a flowchart of one embodiment of a method by which wiretapfunctionality may be provided on an endpoint.

FIG. 18 is a sequence diagram illustrating an exemplary process by whichan endpoint may stream data to one or more other endpoints.

FIG. 19 is a sequence diagram illustrating an exemplary process by whichan endpoint may conduct a private transaction with one or more buddyendpoints.

FIG. 20 is a sequence diagram illustrating an exemplary process by whichan endpoint may conduct a public transaction with one or more otherendpoints.

FIG. 21 is a sequence diagram illustrating an exemplary process by whichan endpoint may establish a conference call with other endpoints.

FIG. 22 is a simplified diagram of another embodiment of a peer-to-peersystem that includes a stateless reflector that may aid an endpoint intraversing a NAT device to communicate with another endpoint.

FIG. 23 is a table illustrating various NAT types and illustrativeembodiments of processes that may be used to traverse each NAT typewithin the system of FIG. 22.

FIG. 24 is a sequence diagram illustrating one embodiment of a processfrom the table of FIG. 23 in greater detail.

FIG. 25 illustrates one embodiment of a modified packet that may be usedwithin the process of FIG. 24.

FIGS. 26-30 are sequence diagrams that each illustrate an embodiment ofa process from the table of FIG. 23 in greater detail.

DETAILED DESCRIPTION

The present disclosure is directed to a system and method forpeer-to-peer hybrid communications. It is understood that the followingdisclosure provides many different embodiments or examples. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. In addition, the present disclosure mayrepeat reference numerals and/or letters in the various examples. Thisrepetition is for the purpose of simplicity and clarity and does not initself dictate a relationship between the various embodiments and/orconfigurations discussed.

Referring to FIG. 1, one embodiment of a peer-to-peer hybrid system 100is illustrated. The system 100 includes an access server 102 that iscoupled to endpoints 104 and 106 via a packet network 108. Communicationbetween the access server 102, endpoint 104, and endpoint 106 isaccomplished using predefined and publicly available (i.e.,non-proprietary) communication standards or protocols (e.g., thosedefined by the Internet Engineering Task Force (IETF) or theInternational Telecommunications Union-Telecommunications StandardSector (ITU-T)). For example, signaling communications (e.g., sessionsetup, management, and teardown) may use a protocol such as the SessionInitiation Protocol (SIP), while actual data traffic may be communicatedusing a protocol such as the Real-time Transport Protocol (RTP). As willbe seen in the following examples, the use of standard protocols forcommunication enables the endpoints 104 and 106 to communicate with anydevice that uses the same standards. The communications may include, butare not limited to, voice calls, instant messages, audio and video,emails, and any other type of resource transfer, where a resourcerepresents any digital data. In the following description, media trafficis generally based on the user datagram protocol (UDP), whileauthentication is based on the transmission control protocol/internetprotocol (TCP/IP). However, it is understood that these are used forpurposes of example and that other protocols may be used in addition toor instead of UDP and TCP/IP.

Connections between the access server 102, endpoint 104, and endpoint106 may include wireline and/or wireless communication channels. In thefollowing description, it is understood that the term “direct” meansthat there is no endpoint or access server in the communicationchannel(s) between the endpoints 104 and 106, or between either endpointand the access server. Accordingly, the access server 102, endpoint 104,and endpoint 106 are directly connected even if other devices (e.g.,routers, firewalls, and other network elements) are positioned betweenthem. In addition, connections to endpoints, locations, or services maybe subscription based, with an endpoint only having access if theendpoint has a current subscription. Furthermore, the followingdescription may use the terms “user” and “endpoint” interchangeably,although it is understood that a user may be using any of a plurality ofendpoints. Accordingly, if an endpoint logs in to the network, it isunderstood that the user is logging in via the endpoint and that theendpoint represents the user on the network using the user's identity.

The access server 102 stores profile information for a user, a sessiontable to track what users are currently online, and a routing table thatmatches the address of an endpoint to each online user. The profileinformation includes a “buddy list” for each user that identifies otherusers (“buddies”) that have previously agreed to communicate with theuser. Online users on the buddy list will show up when a user logs in,and buddies who log in later will directly notify the user that they areonline (as described with respect to FIG. 4). The access server 102provides the relevant profile information and routing table to each ofthe endpoints 104 and 106 so that the endpoints can communicate directlywith one another. Accordingly, in the present embodiment, one functionof the access server 102 is to serve as a storage location forinformation needed by an endpoint in order to communicate with otherendpoints and as a temporary storage location for requests, voicemails,etc., as will be described later in greater detail.

With additional reference to FIG. 2 a, one embodiment of an architecture200 for the access server 102 of FIG. 1 is illustrated. The architecture200 includes functionality that may be provided by hardware and/orsoftware, and that may be combined into a single hardware platform ordistributed among multiple hardware platforms. For purposes ofillustration, the access server in the following examples is describedas a single device, but it is understood that the term applies equallyto any type of environment (including a distributed environment) inwhich at least a portion of the functionality attributed to the accessserver is present.

In the present example, the architecture includes web services 202(e.g., based on functionality provided by XML, SOAP, NET, MONO), webserver 204 (using, for example, Apache or IIS), and database 206 (using,for example, mySQL or SQLServer) for storing and retrieving routingtables 208, profiles 210, and one or more session tables 212.Functionality for a STUN (Simple Traversal of UDP through NATs (NetworkAddress Translation)) server 214 is also present in the architecture200. As is known, STUN is a protocol for assisting devices that arebehind a NAT firewall or router with their packet routing. Thearchitecture 200 may also include a redirect server 216 for handlingrequests originating outside of the system 100. One or both of the STUNserver 214 and redirect server 216 may be incorporated into the accessserver 102 or may be a standalone device. In the present embodiment,both the server 204 and the redirect server 216 are coupled to thedatabase 206.

Referring to FIG. 2 b, one embodiment of an architecture 250 for theendpoint 104 (which may be similar or identical to the endpoint 106) ofFIG. 1 is illustrated. It is understood that that term “endpoint” mayrefer to many different devices having some or all of the describedfunctionality, including a computer, a VoIP telephone, a personaldigital assistant, a cellular phone, or any other device having an IPstack upon which the needed protocols may be run. The architecture 250includes an endpoint engine 252 positioned between a graphical userinterface (GUI) 254 and an operating system 256. The GUI 254 providesuser access to the endpoint engine 252, while the operating system 256provides underlying functionality, as is known to those of skill in theart.

The endpoint engine 252 may include multiple components and layers thatsupport the functionality required to perform the operations of theendpoint 104. For example, the endpoint engine 252 includes a softswitch258, a management layer 260, an encryption/decryption module 262, afeature layer 264, a protocol layer 266, a speech-to-text engine 268, atext-to-speech engine 270, a language conversion engine 272, anout-of-network connectivity module 274, a connection from other networksmodule 276, a p-commerce (e.g., peer commerce) engine 278 that includesa p-commerce agent and a p-commerce broker, and a cellular networkinterface module 280.

Each of these components/layers may be further divided into multiplemodules. For example, the softswitch 258 includes a call control module,an instant messaging (IM) control module, a resource control module, aCALEA (Communications Assistance to Law Enforcement Act) agent, a mediacontrol module, a peer control module, a signaling agent, a fax controlmodule, and a routing module.

The management layer 260 includes modules for presence (i.e., networkpresence), peer management (detecting peers and notifying peers of beingonline), firewall management (navigation and management), mediamanagement, resource management, profile management, authentication,roaming, fax management, and media playback/recording management.

The encryption/decryption module 262 provides encryption for outgoingpackets and decryption for incoming packets. In the present example, theencryption/decryption module 262 provides application level encryptionat the source, rather than at the network. However, it is understoodthat the encryption/decryption module 262 may provide encryption at thenetwork in some embodiments.

The feature layer 264 provides support for various features such asvoice, video, IM, data, voicemail, file transfer, file sharing, class 5features, short message service (SMS), interactive voice response (IVR),faxes, and other resources. The protocol layer 266 includes protocolssupported by the endpoint, including SIP, HTTP, HTTPS, STUN, RTP, SRTP,and ICMP. It is understood that these are examples only, and that feweror more protocols may be supported.

The speech-to-text engine 268 converts speech received by the endpoint(e.g., via a microphone or network) into text, the text-to-speech engine270 converts text received by the endpoint into speech (e.g., for outputvia a speaker), and the language conversion engine 272 may be configuredto convert inbound or outbound information (text or speech) from onelanguage to another language. The out-of-network connectivity module 274may be used to handle connections between the endpoint and externaldevices (as described with respect to FIG. 12), and the connection fromother networks module 276 handles incoming connection attempts fromexternal devices. The cellular network interface module 280 may be usedto interact with a wireless network.

With additional reference to FIG. 2 c, the cellular network interfacemodule 280 is illustrated in greater detail. Although not shown in FIG.2 b, the softswitch 258 of the endpoint architecture 250 includes acellular network interface for communication with the cellular networkinterface module 280. In addition, the cellular network interface module280 includes various components such as a call control module, asignaling agent, a media manager, a protocol stack, and a deviceinterface. It is noted that these components may correspond to layerswithin the endpoint architecture 250 and may be incorporated directlyinto the endpoint architecture in some embodiments.

Referring to FIG. 2 d, a traditional softswitch architecture isillustrated with two endpoints 282 and 284, neither of which includes asoftswitch. In the present example, an external softswitch 286 maintainsa first signaling leg (dotted line) with the endpoint 282 and a secondsignaling leg (dotted line) with the endpoint 284. The softswitch 286links the two legs to pass signaling information between the endpoints282 and 284. Media traffic (solid lines) may be transferred between theendpoints 282 and 284 via a media gateway 287.

With additional reference to FIG. 2 e, the traditional softswitcharchitecture of FIG. 2 d is illustrated with a third endpoint 288 thatalso does not include a softswitch. The external softswitch 286 nowmaintains a third signaling leg (dotted line) with the endpoint 288. Inthe present example, a conference call is underway. However, as none ofthe endpoints includes a softswitch, a media bridge 290 connected toeach endpoint is needed for media traffic. Accordingly, each endpointhas at most two concurrent connections—one with the softswitch forsignaling and another with the media bridge for media traffic.

Referring to FIG. 2 f, in one embodiment, unlike the traditionalarchitecture of FIGS. 2 d and 2 e, two endpoints (e.g., the endpoints104 and 106 of FIG. 1) each include a softswitch (e.g., the softswitch258 of FIG. 2 b). Each endpoint is able to establish and maintain bothsignaling and media traffic connections (both virtual and physical legs)with the other endpoint. Accordingly, no external softswitch is needed,as this model uses a distributed softswitch method to handlecommunications directly between the endpoints.

With additional reference to FIG. 2 g, the endpoints 104 and 106 areillustrated with another endpoint 292 that also contains a softswitch.In this example, a conference call is underway with the endpoint 104acting as the host. To accomplish this, the softswitch contained in theendpoint 104 enables the endpoint 104 to support direct signaling andmedia traffic connections with the endpoint 292. The endpoint 104 canthen forward media traffic from the endpoint 106 to the endpoint 292 andvice versa. Accordingly, the endpoint 104 may support multipleconnections to multiple endpoints and, as in FIG. 2 f, no externalsoftswitch is needed.

Referring again to FIG. 2 b, in operation, the softswitch 258 usesfunctionality provided by underlying layers to handle connections withother endpoints and the access server 102, and to handle services neededby the endpoint 104. For example, as is described below in greaterdetail with respect to FIGS. 3 a and 3 b, incoming and outgoing callsmay utilize multiple components within the endpoint architecture 250.

Referring to FIG. 3 a, a sequence diagram 300 illustrates an exemplaryprocess by which the endpoint 104 may initiate a call to the endpoint106 using various components of the architecture 250. Prior to step 302,a user (not shown) initiates a call via the GUI 254. In step 302, theGUI 254 passes a message to the call control module (of the softswitch258) to make the call. The call control module contacts the peer controlmodule (softswitch 258) in step 304, which detects the peer (if notalready done), goes to the routing table (softswitch 258) for therouting information, and performs similar operations. It is understoodthat not all interactions are illustrated. For example, the peer controlmodule may utilize the peer management module (of the management layer260) for the peer detection. The call control module then identifies aroute for the call in step 306, and sends message to the SIP protocollayer (of the protocol layer 266) to make the call in step 308. In step310, the outbound message is encrypted (using the encryption/decryptionmodule 262) and the message is sent to the network via the OS 256 instep 312.

After the message is sent and prior to receiving a response, the callcontrol module instructs the media control module (softswitch 258) toestablish the needed near-end media in step 314. The media controlmodule passes the instruction to the media manager (of the managementlayer 260) in step 316, which handles the establishment of the near-endmedia.

With additional reference to FIG. 3 b, the message sent by the endpoint104 in step 312 (FIG. 3 a) is received by the endpoint 106 and passedfrom the OS to the SIP protocol layer in step 352. The message isdecrypted in step 354 and the call is offered to the call control modulein step 356. The call control module notifies the GUI of an incomingcall in step 358 and the GUI receives input identifying whether the callis accepted or rejected (e.g., by a user) in step 360. In the presentexample, the call is accepted and the GUI passes the acceptance to thecall control module in step 362. The call control module contacts thepeer control module in step 364, which identifies a route to the callingendpoint and returns the route to the call control module in step 366.In steps 368 and 370, the call control module informs the SIP protocollayer that the call has been accepted and the message is encrypted usingthe encryption/decryption module. The acceptance message is then sent tothe network via the OS in step 372.

In the present example, after the call control module passes theacceptance message to the SIP protocol layer, other steps may occur toprepare the endpoint 106 for the call. For example, the call controlmodule instructs the media control module to establish near-end media instep 374, and the media control module instructs the media manager tostart listening to incoming media in step 376. The call control modulealso instructs the media control module to establish far-end media (step378), and the media control module instructs the media manager to starttransmitting audio in step 380.

Returning to FIG. 3 a, the message sent by the endpoint 106 (step 372)is received by the OS and passed on to the SIP protocol layer in step318 and decrypted in step 320. The message (indicating that the call hasbeen accepted) is passed to the call control module in step 322 and fromthere to the GUI in step 324. The call control module then instructs themedia control module to establish far-end media in step 326, and themedia control module instructs the media manager to start transmittingaudio in step 328.

The following figures are sequence diagrams that illustrate variousexemplary functions and operations by which the access server 102 andthe endpoints 104 and 106 may communicate. It is understood that thesediagrams are not exhaustive and that various steps may be excluded fromthe diagrams to clarify the aspect being described.

Referring to FIG. 4 (and using the endpoint 104 as an example), asequence diagram 400 illustrates an exemplary process by which theendpoint 104 may authenticate with the access server 102 and thencommunicate with the endpoint 106. As will be described, afterauthentication, all communication (both signaling and media traffic)between the endpoints 104 and 106 occurs directly without anyintervention by the access server 102. In the present example, it isunderstood that neither endpoint is online at the beginning of thesequence, and that the endpoints 104 and 106 are “buddies.” As describedabove, buddies are endpoints that have both previously agreed tocommunicate with one another.

In step 402, the endpoint 104 sends a registration and/or authenticationrequest message to the access server 102. If the endpoint 104 is notregistered with the access server 102, the access server will receivethe registration request (e.g., user ID, password, and email address)and will create a profile for the endpoint (not shown). The user ID andpassword will then be used to authenticate the endpoint 104 during laterlogins. It is understood that the user ID and password may enable theuser to authenticate from any endpoint, rather than only the endpoint104.

Upon authentication, the access server 102 updates a session tableresiding on the server to indicate that the user ID currently associatedwith the endpoint 104 is online. The access server 102 also retrieves abuddy list associated with the user ID currently used by the endpoint104 and identifies which of the buddies (if any) are online using thesession table. As the endpoint 106 is currently offline, the buddy listwill reflect this status. The access server 102 then sends the profileinformation (e.g., the buddy list) and a routing table to the endpoint104 in step 404. The routing table contains address information foronline members of the buddy list. It is understood that steps 402 and404 represent a make and break connection that is broken after theendpoint 104 receives the profile information and routing table.

In steps 406 and 408, the endpoint 106 and access server 102 repeatsteps 402 and 404 as described for the endpoint 104. However, becausethe endpoint 104 is online when the endpoint 106 is authenticated, theprofile information sent to the endpoint 106 will reflect the onlinestatus of the endpoint 104 and the routing table will identify how todirectly contact it. Accordingly, in step 410, the endpoint 106 sends amessage directly to the endpoint 104 to notify the endpoint 104 that theendpoint 106 is now online. This also provides the endpoint 104 with theaddress information needed to communicate directly with the endpoint106. In step 412, one or more communication sessions may be establisheddirectly between the endpoints 104 and 106.

Referring to FIG. 5, a sequence diagram 500 illustrates an exemplaryprocess by which authentication of an endpoint (e.g., the endpoint 104)may occur. In addition, after authentication, the endpoint 104 maydetermine whether it can communicate with the endpoint 106. In thepresent example, the endpoint 106 is online when the sequence begins.

In step 502, the endpoint 104 sends a request to the STUN server 214 ofFIG. 2. As is known, the STUN server determines an outbound IP address(e.g., the external address of a device (i.e., a firewall, router, etc.)behind which the endpoint 104 is located), an external port, and a typeof NAT used by the device. The type of NAT may be, for example, fullcone, restricted cone, port restricted cone, or symmetric, each of whichis discussed later in greater detail with respect to FIG. 22. The STUNserver 214 sends a STUN response back to the endpoint 104 in step 504with the collected information about the endpoint 104.

In step 506, the endpoint 104 sends an authentication request to theaccess server 102. The request contains the information about endpoint104 received from the STUN server 214. In step 508, the access server102 responds to the request by sending the relevant profile and routingtable to the endpoint 104. The profile contains the external IP address,port, and NAT type for each of the buddies that are online

In step 510, the endpoint 104 sends a message to notify the endpoint 106of its online status (as the endpoint 106 is already online) and, instep 512, the endpoint 104 waits for a response. After the expiration ofa timeout period within which no response is received from the endpoint106, the endpoint 104 will change the status of the endpoint 106 from“online” (as indicated by the downloaded profile information) to“unreachable.” The status of a buddy may be indicated on a visual buddylist by the color of an icon associated with each buddy. For example,when logging in, online buddies may be denoted by a blue icon andoffline buddies may be denoted by a red icon. If a response to a notifymessage is received for a buddy, the icon representing that buddy may bechanged from blue to green to denote the buddy's online status. If noresponse is received, the icon remains blue to indicate that the buddyis unreachable. Although not shown, a message sent from the endpoint 106and received by the endpoint 104 after step 514 would indicate that theendpoint 106 is now reachable and would cause the endpoint 104 to changethe status of the endpoint 106 to online Similarly, if the endpoint 104later sends a message to the endpoint 106 and receives a response, thenthe endpoint 104 would change the status of the endpoint 106 to online.

It is understood that other embodiments may implement alternate NATtraversal techniques. For example, a single payload technique may beused in which TCP/IP packets are used to traverse a UDP restrictedfirewall or router. Another example includes the use of a double payloadin which a UDP packet is inserted into a TCP/IP packet. Furthermore, itis understood that protocols other than STUN may be used. For example,protocols such as Internet Connectivity Establishment (ICE) or TraversalUsing Relay NAT (TURN) may be used.

Referring to FIG. 6, a sequence diagram 600 illustrates an exemplaryprocess by which the access server 102 may aid the endpoint 104 inestablishing communications with the endpoint 106 (which is a buddy).After rendering aid, the access server 102 is no longer involved and theendpoints may communicate directly. In the present example, the endpoint106 is behind a NAT device that will only let a message in (towards theendpoint 106) if the endpoint 106 has sent a message out. Unless thisprocess is bypassed, the endpoint 104 will be unable to connect to theendpoint 106. For example, the endpoint 104 will be unable to notify theendpoint 106 that it is now online.

In step 602, the endpoint 106 sends a request to the STUN server 214 ofFIG. 2. As described previously, the STUN server determines an outboundIP address, an external port, and a type of NAT for the endpoint 106.The STUN server 214 sends a STUN response back to the endpoint 106 instep 604 with the collected information about the endpoint 106. In step606, the endpoint 106 sends an authentication request to the accessserver 102. The request contains the information about endpoint 106received from the STUN server 214. In step 608, the access server 102responds to the request by sending the relevant profile and routingtable to the endpoint 106. In the present example, the access server 102identifies the NAT type associated with the endpoint 106 as being a typethat requires an outbound packet to be sent before an inbound packet isallowed to enter. Accordingly, the access server 102 instructs theendpoint 106 to send periodic messages to the access server 102 toestablish and maintain a pinhole through the NAT device. For example,the endpoint 106 may send a message prior to the timeout period of theNAT device in order to reset the timeout period. In this manner, thepinhole may be kept open indefinitely.

In steps 612 and 614, the endpoint 104 sends a STUN request to the STUNserver 214 and the STUN server responds as previously described. In step616, the endpoint 104 sends an authentication request to the accessserver 102. The access server 102 retrieves the buddy list for theendpoint 104 and identifies the endpoint 106 as being associated with aNAT type that will block communications from the endpoint 104.Accordingly, in step 618, the access server 102 sends an assist messageto the endpoint 106. The assist message instructs the endpoint 106 tosend a message to the endpoint 104, which opens a pinhole in the NATdevice for the endpoint 104. For security purposes, as the access server102 has the STUN information for the endpoint 104, the pinhole opened bythe endpoint 106 may be specifically limited to the endpoint associatedwith the STUN information. Furthermore, the access server 102 may notrequest such a pinhole for an endpoint that is not on the buddy list ofthe endpoint 106.

The access server 104 sends the profile and routing table to theendpoint 104 in step 620. In step 622, the endpoint 106 sends a message(e.g., a ping packet) to the endpoint 104. The endpoint 104 may thenrespond to the message and notify the endpoint 106 that it is nowonline. If the endpoint 106 does not receive a reply from the endpoint104 within a predefined period of time, it may close the pinhole (whichmay occur simply by not sending another message and letting the pinholetime out). Accordingly, the difficulty presented by the NAT device maybe overcome using the assist message, and communications between the twoendpoints may then occur without intervention by the access server 102.

Referring to FIG. 7, a sequence diagram 700 illustrates an exemplaryprocess by which the endpoint 106 may request that it be added to theendpoint 104's buddy list. In the present example, the endpoints 104 and106 both remain online during the entire process.

In step 702, the endpoint 104 sends a registration and/or authenticationrequest message to the access server 102 as described previously. Uponauthentication, the access server 102 updates a session table residingon the server to indicate that the user ID currently associated with theendpoint 104 is online. The access server 102 also retrieves a buddylist associated with the user ID currently used by the endpoint 104 andidentifies which of the buddies (if any) are online using the sessiontable. As the endpoint 106 is not currently on the buddy list, it willnot be present. The access server 102 then sends the profile informationand a routing table to the endpoint 104 in step 704.

In steps 706 and 708, the endpoint 106 and access server 102 repeatsteps 702 and 704 as described for the endpoint 104. The profileinformation sent by the access server 102 to the endpoint 106 will notinclude the endpoint 104 because the two endpoints are not buddies.

In step 710, the endpoint 106 sends a message to the access server 102requesting that the endpoint 104 be added to its buddy list. The accessserver 102 determines that the endpoint 104 is online (e.g., using thesession table) in step 712 and sends the address for the endpoint 104 tothe endpoint 106 in step 714. In step 716, the endpoint 106 sends amessage directly to the endpoint 104 requesting that the endpoint 106 beadded to its buddy list. The endpoint 104 responds to the endpoint 106in step 718 with either permission or a denial, and the endpoint 104also updates the access server 102 with the response in step 720. Forexample, if the response grants permission, then the endpoint 104informs the access server 102 so that the access server can modify theprofile of both endpoints to reflect the new relationship. It isunderstood that various other actions may be taken. For example, if theendpoint 104 denies the request, then the access server 102 may notrespond to another request by the endpoint 106 (with respect to theendpoint 104) until a period of time has elapsed.

It is understood that many different operations may be performed withrespect to a buddy list. For example, buddies may be deleted,blocked/unblocked, buddy status may be updated, and a buddy profile maybe updated. For block/unblock, as well as status and profile updates, amessage is first sent to the access server 102 by the endpointrequesting the action (e.g., the endpoint 104). Following the accessserver 102 update, the endpoint 104 sends a message to the peer beingaffected by the action (e.g., the endpoint 106).

Buddy deletion may be handled as follows. If the user of the endpoint104 wants to delete a contact on a buddy list currently associated withthe online endpoint 106, the endpoint 104 will first notify the accessserver 102 that the buddy is being deleted. The access server 102 thenupdates the profile of both users so that neither buddy list shows theother user as a buddy. Note that, in this instance, a unilateral actionby one user will alter the profile of the other user. The endpoint 104then sends a message directly to the endpoint 106 to remove the buddy(the user of the endpoint 104) from the buddy list of the user ofendpoint 106 in real time. Accordingly, even though the user is onlineat endpoint 106, the user of the endpoint 104 will be removed from thebuddy list of the endpoint 106

Referring to FIG. 8, a sequence diagram 800 illustrates an exemplaryprocess by which the endpoint 106 may request that it be added to theendpoint 104's buddy list. In the present example, the endpoint 104 isnot online until after the endpoint 106 has made its request.

In step 802, the endpoint 106 sends a registration and/or authenticationrequest message to the access server 102 as described previously. Uponauthentication, the access server 102 updates a session table residingon the server to indicate that the user ID currently associated with theendpoint 106 is online. The access server 102 also retrieves a buddylist associated with the user ID currently used by the endpoint 106 andidentifies which of the buddies (if any) are online using the sessiontable. The access server 102 then sends the profile information and arouting table to the endpoint 106 in step 804.

In step 806, the endpoint 106 sends a message to the access server 102requesting that the endpoint 104 be added to its buddy list. The accessserver 102 determines that the endpoint 104 is offline in step 808 andtemporarily stores the request message in step 810. In steps 812 and814, the endpoint 104 and access server 102 repeat steps 802 and 804 asdescribed for the endpoint 106. However, when the access server 102sends the profile information and routing table to the endpoint 104, italso sends the request by the endpoint 106 (including addressinformation for the endpoint 106).

In step 816, the endpoint 104 responds directly to the endpoint 106 witheither permission or a denial. The endpoint 104 then updates the accessserver 102 with the result of the response in step 818 and alsoinstructs the access server to delete the temporarily stored request.

Referring to FIG. 9, a sequence diagram 900 illustrates an exemplaryprocess by which the endpoint 106 may request that it be added to theendpoint 104's buddy list. In the present example, the endpoint 104 isnot online until after the endpoint 106 has made its request, and theendpoint 106 is not online to receive the response by endpoint 104.

In step 902, the endpoint 106 sends a registration and/or authenticationrequest message to the access server 102 as described previously. Uponauthentication, the access server 102 updates a session table residingon the server to indicate that the user ID currently associated with theendpoint 106 is online. The access server 102 also retrieves a buddylist associated with the user ID currently used by the endpoint 106 andidentifies which of the buddies (if any) are online using the sessiontable. The access server 102 then sends the profile information and arouting table to the endpoint 106 in step 904.

In step 906, the endpoint 106 sends a message to the access server 102requesting that the endpoint 104 be added to its buddy list. The accessserver 102 determines that the endpoint 104 is offline in step 908 andtemporarily stores the request message in step 910. In step 912, theendpoint 106 notifies the access server 102 that it is going offline.

In steps 914 and 916, the endpoint 104 and access server 102 repeatsteps 902 and 904 as described for the endpoint 106. However, when theaccess server 102 sends the profile information and routing table to theendpoint 104, it also sends the request by the endpoint 106. Endpoint104 sends its response to the access server 102 in step 918 and alsoinstructs the access server to delete the temporarily stored request.After the endpoint 106's next authentication process, its profileinformation will include endpoint 104 as a buddy (assuming the endpoint104 granted permission).

Referring to FIG. 10, a sequence diagram 1000 illustrates an exemplaryprocess by which the endpoint 106 may store a voicemail for the endpoint104. In the present example, the endpoint 106 is online, but is notavailable to take the call.

In step 1002, the endpoint 104 sends a call request message to theendpoint 106 requesting that a call be established between the twoendpoints. In step 1004, the endpoint 106 responds with a messageindicating that it is busy and cannot take the call. In step 1006, afterrecording a voicemail (not shown), the endpoint 104 sends the voicemailto the access server 102, which temporarily stores the voicemail in step1008. The endpoint 104 then sends a message (e.g., a message waitingindicator (MWI)) to the endpoint 106 in step 1010 before sending thevoicemail to the endpoint 106 in step 1012. The endpoint 106 receivesthe voicemail in step 1014 (e.g., after ending the previous call) andinstructs the access server 102 to delete the temporarily storedvoicemail in step 1016. It is understood that the endpoint 106 mayperform many different actions with respect to the voicemail, includingsaving, forwarding, responding, etc.

Referring to FIG. 11, a sequence diagram 1100 illustrates an exemplaryprocess by which the endpoint 106 may receive a voicemail from theendpoint 104. In the present example, the endpoint 106 is offline whenthe voicemail is recorded and sent. In step 1102, the endpoint 104determines that the endpoint 106 is offline. As described previously,such a determination may be made based on the fact that the endpoint 106was not online when the endpoint 104 was authenticated (as indicated bythe profile information from the access server 102) and has not sincelogged in (as it would have notified the endpoint 104 as described withrespect to FIG. 4). As the endpoint 106 is offline, the endpoint 104sends a recorded voicemail to the access server 102 in step 1104, whichtemporarily stores the voicemail in step 1106. The endpoint 106authenticates with the access server 102 in step 1108 as previouslydescribed, and the access server sends the endpoint 106 the relevantprofile information and routing table in step 1110. In addition to theinformation normally sent to the endpoint 106 after authentication, theaccess server 102 sends a message such as a message waiting indicator toinform the endpoint 106 of the stored voicemail. In steps 1112 and 1114,the endpoint 106 retrieves the recorded voicemail and instructs theaccess point 102 to delete the voicemail from the server.

Referring to FIG. 12, in another embodiment, the system 100 of FIG. 1 isillustrated as a “home system” that forms part of a larger system 1200.The home system includes all endpoints that have registered with theaccess server 102. In addition to the home system 100, a number ofexternal (relative to the home system 100) devices are illustrated,including an external endpoint 1202 (e.g., a SIP capable such as a SIPtelephone, a computer, a personal digital assistant, a householdappliance, or an automated control system for a business or residence).Additional external devices include a gateway 1204 and an IPPBX 1206,both of which are coupled to a PSTN 1208. The gateway 1204 is alsocoupled to a cellular network 1210, which includes a radio accessnetwork, core network, and other cellular network components (notshown). In the present example, both the gateway 1204 and the IPPBX 1206include a non-proprietary interface (e.g., a SIP interface) that enablesthem to communicate directly with the SIP-based endpoints 104 and 106.It is understood that various portions of the system 1200 may includewired and/or wireless interfaces and components.

The endpoints 104 and 106 that are within the home system 100 areauthenticated by the access server 102 using user-supplied credentials(as previously described). Communication may occur directly between theendpoints 104, 106 and devices outside of the home system 100 asfollows. The access server 102 serves as a routing table repository. Asdescribed previously, a routing table contains information needed by theendpoints 104, 106 in order to connect to buddies within the homenetwork 100. In the present example, the routing table (or anotherrouting table) also contains information needed by the endpoints 104,106 in order to connect to the external devices. Connections to externaldevices, locations, or services may be subscription based, with therouting table for a particular endpoint only having address informationfor external devices for which the endpoint has a current subscription.For example, the profile associated with the endpoint 104 may have aflag representing whether the endpoint is subscribed to a service suchas a PSTN calling plan.

Referring to FIG. 13, a sequence diagram 1300 illustrates an exemplaryprocess by which the endpoint 104 may directly contact the externalendpoint 1202 within the system 1200 of FIG. 12. The endpoint 1202 isonline and the endpoint 104 has the authority (e.g., a subscription) tocontact the endpoint 1202. Although the present example uses SIP forsignaling and RTP for media traffic, it is understood that otherprotocols may be used.

In step 1302, the endpoint 104 sends an authentication request messageto the access server 102 as described previously. After authentication,the access server 102 sends the profile information and a routing tableto the endpoint 104 in step 1304. After the endpoint 104 has beenauthenticated, the user of the endpoint places a call (e.g., a VoIPcall) to the endpoint 1202. In step 1306, the endpoint 104 performsdigit collection and analysis on the number entered by the user. Asendpoint 104 contains both the routing table and a softswitch, theendpoint is able to identify and place the call directly to the endpoint1202.

In step 1308, the endpoints 104 and 106 setup the call. For example, theendpoint 104 may sent a SIP INVITE message directly to the endpoint1202. The endpoint 104 must provide any credentials required by theendpoint 1202. The endpoint 1202 responds with a 200 OK message and theendpoint 104 responds with an ACK message. The endpoints 104 and 1202may then use an RTP session (step 1310) for the VoIP call. After the RTPsession is complete, call teardown occurs in step 1312. Accordingly, asdescribed in the previous examples between endpoints in the home system100, the endpoint 104 directly contacts the endpoint 1202 (or gateway1204 or IPPBX 1206) without intervention by the access server 102 afterdownloading the profile and routing table during authentication.

Another external endpoint 1212 may be contacted in the same manner asthe endpoint 1202, although the communications will need to be routedthrough the gateway 1204 and cellular network 1210. As with the endpoint1202, the endpoint 104 may contact the endpoint 1212 directly withoutintervention from the access server 102.

Referring to FIG. 14, a method 1400 illustrates one possible sequence ofevents for utilizing the routing tables of the access server 102 forexternal communications. The method begins in step 1402 when an endpoint(e.g., the endpoint 104) authenticates with the access server 102. Theendpoint 104 downloads one or more routing tables in step 1404,depending on such factors as whether the endpoint 104 has a subscriptionto a relevant service (e.g., whether the endpoint 104 allowed to calloutside of the home network). The routing tables are downloaded in a rawdata format, and the endpoint 104 processes the raw data in step 1406 toproduce optimal routing rules in step 1408. At this point, the endpoint104 may use the routing rules to communicate with other endpoints.

The routing tables may change on the access server 102. For example, anew service area or new subscription options may become accessible.However, unless the endpoint 104 logs off and back on, the endpoint willnot be aware of these changes. Accordingly, the access server 102 sendsa notification in step 1410 that changes have occurred to the routingtables. In step 1412, the endpoint 104 determines whether a change hasoccurred with respect to the routing tables on the endpoint. Forexample, if the endpoint 104 just logged on, it may have the updatedrouting tables. Alternatively or additionally, the notification may notindicate which routing tables have changed, and the endpoint 104 willneed to determine if any of the routing tables that it uses havechanged.

If the routing tables have changed, the endpoint 104 makes adetermination in step 1414 as to whether the change is relatively largeor is minor. If the change is large, the method returns to step 1404,where the routing tables are downloaded. If the changes are minor, themethod continues to step 1416, where the endpoint 104 updates itsrouting tables (e.g., the endpoint 104 downloads only the changedinformation). It is understood that some processing may be needed toprepare the new information for insertion into the existing routingrules.

If a call to an external device is to be placed (step 1418), theendpoint 104 determines whether it has a match in its routing rules instep 1420. If a match exists, the endpoint 104 uses the routing rules toroute the call to an appropriate gateway or endpoint in step 1422. If nomatch exists, the endpoint 104 has insufficient information to route thecall (step 1424) and ends the call process.

Referring to FIG. 15, a sequence diagram 1500 illustrates an exemplaryprocess by which the external endpoint 1202 may attempt to establishcontact with the endpoint 104 within the system 1200 of FIG. 12 usingSIP messaging. In step 1502, the endpoint 1202 sends a SIP INVITEmessage to a redirect server (e.g., the redirect server 216 of FIG. 2a). The redirect server 216 accesses a database (e.g., the database 206of FIG. 2 a) in step 1504 and obtains contact information for theendpoint 104. The information may also include credentials (e.g., ausername and password) required by the endpoint 104. If credentials arerequired, the redirect server 216 sends a message to the endpoint 1202in step 1506 requesting the credentials. The endpoint 1202 responds tothe credentials request in step 1508 by sending a SIP INVITE containingthe credentials to the redirect server 216. The redirect server 216 thensends a redirect message to the endpoint 1202 with the addressinformation for the endpoint 104 in step 1510. In step 1512, theendpoint 1202 may then directly contact the endpoint 104 with a SIPINVITE message. If the endpoint 104 is not available (e.g., offline),the redirect server 216 may send a message to the endpoint 1202 that theendpoint 104 is not available.

Referring again to FIG. 12, in the present example, the home system 100includes a resource server 1214. Although the resource server 1214 maybe part of the access server 102, it is separated into a separate serverfor purposes of illustration. The access server 102 and resource server1214 may be in communication with one another (not shown) for purposesof identifying access rights and similar issues. The resource server1214 stores and distributes various resources to the endpoints 104 and106. As described previously, a resource represents any type of digitaldata. In operation, an endpoint (e.g., the endpoint 104) may store aresource on the resource server 1214 for later retrieval by the endpoint106 or may transfer the resource directly to the endpoint 106.Furthermore, the resource server 1214 may distribute the resource to theendpoint 106, as well as to other endpoints. In this manner, theresource server 1214 may serve as temporary or permanent storage. Insome embodiments, the resource server 1214 may restrict access based oncredentials provided by the endpoints 104 and 106. For example, if theendpoint 104 only has the credentials for certain resources, then theresource server may limit the endpoint's access to those resources.Communication between an endpoint and the resource server occursdirectly as described above with respect to two endpoints.

It is understood that many different methods may be implemented usingthe endpoints and/or access server described above. Various methods aredescribed below as examples, but it is understood that many othermethods or variations of methods are possible.

In one embodiment, a port rotation method may be implemented that allowsfor changing/rotating the port used to listen for communications toprovide added security. The rotation may occur during idle time of theoperation of the endpoint. For example, when idle time is detected, arandom unused port is selected. The endpoint then informs the accessserver of the new route information and sends out a peer-to-peernotification to all online buddies to notify them of the change in theport/route information.

In another embodiment, wireless calls may be made through an endpoint.For example, a method may be implemented that allows for a directinterface (e.g., using the cellular network interface 280 of FIGS. 2 b)to 3G or any similar wireless network directly from the endpoint in apeer-to-peer hybrid system. When the endpoint is activated, the wirelessmodule informs the wireless network of its presence. At this point,calls can be sent to and received from the wireless network. Theendpoint can also bridge calls from the wireless side to the IP side ofthe network. For example, if a call is received from a wireless phone atthe endpoint via the wireless interface, the endpoint's user can chooseto route calls to any buddy endpoints on the IP side of the network.This bridging functionality is another capability of the endpoint.Similarly, calls received on the IP side can be bridged to the wirelessside.

Referring to FIG. 16, in another embodiment, a method 1600 may be usedwith interactive voice response (IVR) (e.g., the IVR support provided bythe feature layer 264 of FIG. 2 b) to automatically handle calls when anauto-attendant is turned on. The auto-attendant provides functionalitythat allows users to perform other tasks when they are busy or notpresent to attend to calls or other forms of communication. The method1600 may automatically terminate calls on behalf of the user and performother tasks as defined by the user (e.g., leave a message or be routedto another destination).

In the present example, the method 1600 begins in step 1602 when theendpoint (e.g., the endpoint 104) receives a call. In step 1604, adetermination is made as to whether the auto-attendant is enabled (e.g.,whether IVR functionality is on). If it is not enabled, the methodcontinues to step 1606, where the call is processed normally. If it isenabled, the call is accepted and the IVR functionality is started instep 1608. In step 1610, the call is connected.

Referring to FIG. 17, in still another embodiment, a method 1700 may beused to provide wiretap functionality on an endpoint (e.g., the endpoint104). Such functionality may be provided, for example, by the CALEAagent of the softswitch 258 of FIG. 2 b. The method begins in step 1702when the endpoint 104 makes or received a call. If the endpoint is beingtapped, as determined in step 1704, the method will continue to step1706, where the start of the call will be logged. The method 1700 thencontinues to step 1708, where the call is established. If the endpointis not being tapped, the method skips step 1706 and proceeds directly tostep 1708. In step 1710, a determination is made as to whether mediaassociated with the call is to be captured. If so, the media is capturedand securely streamed to a designated law enforcement agency in step1712. The method then continues to step 1714, where call tear downoccurs after the call is ended. If no media is to be captured, themethod proceeds directly from step 1710 to step 1714. In step 1718, theend of the call is logged (if a wiretap is enabled as determined in step1716) and the endpoint 104 returns to an idle state in step 1720. In thepresent example, the log information is also securely streamed to thelaw enforcement agency as it is captured.

In another embodiment, a Find Me Follow Me (roaming) method may be usedto provide simultaneous multiple sessions for the endpoint in thepeer-to-peer hybrid environment. The endpoints can be signed in atmultiple locations to access services offered and communicate directlyin a peer-to-peer manner with other endpoints that are buddies. In thismethod, when one endpoint tries to contact his/her buddy, if the buddyis signed on at multiple locations, the originating buddy sends outmessages to all signed in locations of the buddy. When the endpointresponds from any one of the multiple signed in locations, requests toother endpoints are dropped and communication is continued with theendpoint that has accepted the request for communication.

Referring to FIG. 18, in still another embodiment, a sequence diagram1800 illustrates an exemplary process by which the endpoint 104 maystream data in real time to one or more other buddy endpoints 106 and292 (FIG. 2 g), either one at a time or simultaneously. In steps 1802and 1804, respectively, the originating endpoint (e.g., the endpoint104) sends out a request to stream data to the endpoints 106 and 292.The endpoints receiving the request may respond with messages eitheraccepting or rejecting the request (steps 1806 and 1808). Once therequest is accepted (as indicated in step 1810), the data stream is sentout to all buddies that have accepted the request for the data stream(steps 1812 and 1814). On the terminating endpoints 106 and 292, theuser chooses an application that can handle the processing of the datastream to utilize the data. It is understood that some applications maybe automatically selected by the endpoint for recognized or predefineddata types. The streams are then processed by the relevant endpoint(steps 1816 and 1818). In steps 1820 and 1822, respectively, theendpoint 104 sends out a request to the endpoints 106 and 292 toterminate the stream. The endpoints 106 and 292 stop their processing insteps 1824 and 1826, respectively.

In yet another embodiment, a method for Smart IM.™. (as developed byDamaka, Inc., of Richardson, Tex.) or Enhanced IM may be used to converttextual data sent to and received by the endpoint into speech byemploying a text-to-speech recognition system in real-time. Textual datacan be received from the network or locally for conversion tospeech/voice signals for playback. Such functionality may be provided,for example, by the text-to-speech engine 270 of FIG. 2 b.

In another embodiment, a method to convert speech/voice data that issent to and received by the endpoint into text form by employing aspeech-to-text system in real-time. Speech/voice data can be receivedfrom the network or locally for conversion to text data for processingby the user. Such functionality may be provided, for example, by thespeech-to-text engine 268 of FIG. 2 b.

In one embodiment, a method may be used to provide correction services(e.g., spell check) on textual data being sent/received by the endpoint.In another embodiment, a method may provide functionality to allow auser to search the world wide web or internet via search engines foradditional information related to textual data being sent/received bythe endpoint. In yet another embodiment, a method may providefunctionality for performing language conversion on textual data beingsent/received by the endpoint using one or more language conversionengines (e.g., the language conversion engine 272 of FIG. 2 b.).

In still another embodiment, a method may provide functionality enablingtextual data received by the endpoint to be archived on the endpoint forlater retrieval. For example, a database (e.g., SQL) engine may be usedto store and index data received by the endpoint from a buddy for fasterretrieval. A standard query interface may then be used to store/retrievedata for presentation to the user.

In another embodiment, a method may be used to provide SMSfunctionality. Such functionality may be provided, for example, by theSMS feature of the feature layer 264 of FIG. 2 b. For example, an SMStable may be downloaded with the routing table when an endpoint logsonto the network. If the endpoint has a mobile setting, the endpoint maybe able to communicate directly via the SMS functionality.

Referring to FIG. 19, in another embodiment, a sequence diagram 1900illustrates an exemplary process by which the endpoint 104 may initiatea private transaction (e.g., make an offer for sale or start an auctionprocess) to buddies represented by endpoints 106 and 292 (FIG. 2 g). Insteps 1902 and 1904, respectively, the endpoint 104 sends a messagecontaining an offer to sale one or more items to the endpoints 106 and292. In steps 1906 and 1908, respectively, the endpoints 106 and 292 mayreturn messages accepting or rejecting the offer, or making acounteroffer. The user of the endpoint 104 may review the receivedmessages and accept one, reject both, reply to one or both with anadditional counteroffer, etc., in step 1910. This process (offer,response, review) may continue until the offer is either finallyaccepted or rejected. In the present example, because the interactionoccurs between buddies, the actual financial transaction may not occurelectronically.

Referring to FIG. 20, in yet another embodiment, a sequence diagram 2000illustrates an exemplary process by which the endpoint 104 may initiatea public transaction (e.g., make an offer or start an auction process).In step 2002, the endpoint 104 sends a message to the access server 102to post a sale. The message contains information such as a descriptionof the item for sale, a starting price, and the start/end dates of theauction. In step 2004, the endpoint 106 (which is not a buddy in thepresent example) obtains the sale information from the server. Theobtained information includes a “substitute ID” of the endpoint 104 andassociated address information. The substitute ID, which may be assignedto the endpoint 104 exclusively for the sale, enables the endpoint 106to contact the endpoint 104 directly without obtaining the actual ID ofthe user of the endpoint 104. Accordingly, when the sale ends, theendpoint 106 will no longer be able to contact the endpoint 104.

In step 2006, the endpoint 106 sends a message directly to the endpoint104 with a bid. In step 2008, the endpoint 104 updates the informationon the access server with the bid and bidder information. Although notshown, buddy endpoints may also bid on the posted item. In step 2010,the user of the endpoint 104 reviews the bids, selects a winner (if awinner exists), and notifies the winner directly (step 2012). In step2014, the sale transaction is handled. In the present example, becausethe transaction may occur between parties that are not buddies, thetransaction may be accomplished via a third party clearinghouse.However, if a buddy won the sale, the parties may revert to a privatetransaction. Additionally, it is understood that any parties (whether ornot they are buddies) may arrange the transaction as desired. In someembodiments, the process may include directly or indirectly notifyinginvolved parties of a pending bid, notifying involved parties ofaccepted/rejected bids, etc. The seller may also accept any bid desired(e.g., not only the highest bid) and may end the bidding at any time. Ifan endpoint is offline when bidding occurs (e.g., if the endpoint 104 isoffline when the message of step 2006 is sent or if the endpoint 106 isoffline when the message of step 2012 is sent), the message may bedownloaded during authentication when the endpoint logs in as previouslydescribed.

Referring to FIG. 21, in still another embodiment, a sequence diagram2100 illustrates an exemplary process by which the endpoint 104 mayinitiate a conference call with other endpoints (e.g., the endpoints 106and 1202, both of which are buddies with the endpoint 104 in the presentexample). It is noted that the endpoints 106 and 1202 may or may not bebuddies with each other. In steps 2102 and 2104, respectively, theendpoint 104 sends a request to join a conference call to the endpoints106 and 1202. The endpoints 106 and 1202 respond in steps 2106 and 2108,respectively, by either accepting or rejecting the request. In thepresent example, both endpoints 106 and 1202 accept the request (asindicated by step 2110).

The endpoint 104 may then send media (e.g., text or voice information)to the endpoints 106 and 1202 in steps 2112 and 2114, respectively.Incoming media (e.g., from the endpoint 106) is received by the endpoint104 in step 2116 and sent to the endpoint 1202 by the endpoint 104 instep 2118. In the present example, rather than multicasting theinformation, the endpoint 104 hosts the conference call by using aseparate peer-to-peer connection with each endpoint. As the endpoints106 and 1202 are connected in the conference call via the endpoint 104and are not communicating with each other directly, the endpoints 106and 1202 do not need to be buddies. Accordingly, the endpoint 104 in thepresent example may have two routing entries associated with theconference call: one routing entry for endpoint 106 and another routingentry for endpoint 1202. In other embodiments, multicasting may be usedto transmit the data from the endpoint 104 to the endpoints 106 and1202.

It is understood that the process described with respect to FIG. 21 maybe applied to other scenarios. For example, the endpoint 104 may serveas the host for a multiplayer game. Incoming data may then bedistributed by the endpoint to other endpoints that are associated withthe hosted game.

Referring to FIG. 22, in one embodiment, a system 2200 includes astateless reflector 2202 and two endpoints 104 and 106, such as theendpoints 104 and 106 described with respect to the preceding figures.In the present example, each of the endpoints 104 and 106 are behind adevice 2204, 2206, respectively, that monitors and regulatescommunication with its respective endpoint. Each device 2204, 2206 inthe present example is a firewall having NAT technology. As describedpreviously, a NAT device may present an obstacle in establishing apeer-to-peer connection because it may not allow unsolicited messages(e.g., it may require a packet to be sent out through the NAT devicebefore allowing a packet in). For example, the NAT device 2206positioned between the endpoint 106 and network 108 may only let amessage in (towards the endpoint 106) if the endpoint 106 has sent amessage out. Unless the NAT device's status is shifted from notsoliciting messages from the endpoint 104 to soliciting messages fromthe endpoint 104, the endpoint 104 will be unable to connect to theendpoint 106. For example, the endpoint 104 will be unable to notify theendpoint 106 that it is now online.

As will be described below in greater detail, the stateless reflector2202 is configured to receive one or more packets from an endpoint andreflect the packet to another endpoint after modifying informationwithin the packet. This reflection process enables the endpoints 104 and106 to communicate regardless of the presence and type of the NATdevices 2204 and 2206. The stateless reflector 2202 is stateless becausestate information (e.g., information relating to how an endpoint is toconnect with other endpoints) is stored by the endpoints, as describedpreviously. Accordingly, the stateless reflector 2202 processes headerinformation contained within a packet without access to otherinformation about the network or endpoints, such as the database 206 ofFIG. 2 a. Although only one stateless reflector 2202 is illustrated inFIG. 22, it is understood that multiple stateless reflectors may beprovided, and that the endpoints 104 and 106 may each use a differentstateless reflector. For example, an endpoint may be configured to use aparticular stateless reflector or may select a stateless reflector basedon location, NAT type, etc.

Although each endpoint 104, 106 is shown with a separate NAT device2204, 2206, it is understood that multiple endpoints may be connected tothe network 108 via a single NAT device. For example, a LAN may accessthe network 108 via a single NAT device, and all communications betweenthe endpoints connected to the LAN and the network 108 must pass throughthe NAT device. However, communications between the endpoints within theLAN itself may occur directly, as previously described, because theendpoints are not communicating through the NAT device. Furthermore, ifone of the endpoints 104 or 106 does not have a NAT device, thencommunications with that endpoint may occur directly as described aboveeven if the endpoints are not in the same network.

Each NAT device 2204 and 2206 includes an internal IP address (on theside coupled to the endpoint 104 for the NAT device 2204 and the sidecoupled to the endpoint 106 for the NAT device 2206) and an external IPaddress (on the side coupled to the network 108 for both NAT devices).Each connection is also associated with an internal port and an externalport. Therefore, each connection includes both internal IP address/portinformation and external IP address/port information.

Generally, a NAT device may be defined as full cone, restricted cone,port restricted cone, or symmetric. A full cone NAT is one where allrequests from the same internal IP address and port are mapped to thesame external IP address and port. Therefore, any external host can senda packet to the internal host by sending a packet to the mapped externaladdress.

A restricted cone NAT is one where all requests from the same internalIP address and port are mapped to the same external IP address and port.Unlike a full cone NAT, an external host can send a packet to theinternal host only if the internal host has previously sent a packet tothe external host's IP address.

A port restricted cone NAT is like a restricted cone NAT, but therestriction includes port numbers. More specifically, an external hostcan send a packet with source IP address X and source port P to theinternal host only if the internal host has previously sent a packet tothe external host at IP address X and port P.

A symmetric NAT is one where all requests from the same internal IPaddress and port to a specific destination IP address and port aremapped to the same external IP address and port. If the same host sendsa packet with the same source address and port, but to a differentdestination, a different mapping is used. Only the external host thatreceives a packet can send a UDP packet back to the internal host.

Referring to FIG. 23, a table 2300 illustrates one embodiment of acommunication structure that may be used to traverse one or both of theNAT devices 2204 and 2206 of FIG. 22. The table 2300 provides fivepossible types for the NAT devices 2204 and 2206: no NAT, full cone,restricted cone, port restricted cone, and symmetric. It is understoodthat “no NAT” may indicate that no device is there, that a device isthere but does not include NAT functionality, or that a device is thereand any NAT functionality within the device has been disabled. Either ofthe NAT devices 2204 and 2206 may be on the originating side of thecommunication or on the terminating side. For purposes of convenience,the endpoint 104 is the originating endpoint and the endpoint 106 is theterminating endpoint, and the NAT device 2204 is the originating NATdevice and the NAT device 2206 is the terminating NAT device. It isunderstood that the terms “endpoint” and “NAT device” may be usedinterchangeably in some situations. For example, sending a packet to theendpoint 106 generally involves sending a packet to the NAT device 2206,which then forwards the packet to the endpoint 106 after performing thenetwork address translation. However, the following discussion maysimply refer to sending a packet to the endpoint 106 and it will beunderstood that the packet must traverse the NAT device 2206.

As illustrated by the table 2300, there are twenty-five possiblepairings of NAT types and establishing communication between differentNAT types may require different steps. For purposes of convenience,these twenty-five pairings may be grouped based on the required steps.For example, if the originating NAT type is no NAT, full cone,restricted cone, or port restricted cone, then the originating NAT canestablish communication directly with a terminating NAT type of eitherno NAT or full cone.

If the originating NAT type is no NAT or full cone, then the originatingNAT can establish communications with a terminating NAT type of eitherrestricted cone or port restricted cone only after using the statelessreflector 2202 to reflect a packet. This process is described below withrespect to FIG. 24.

Referring to FIG. 24, the endpoint 104 wants to inform the endpoint 106,which is already logged on, that the endpoint 104 has logged on. The NATdevice 2204 is either a no NAT or a full cone type and the NAT device2206 is either a restricted cone or a port restricted cone type.Accordingly, the endpoint 104 wants to send a message to the endpoint106, but has not received a message from the endpoint 106 that wouldallow the endpoint 104 to traverse the NAT device 2206.

Although not shown in FIG. 24, prior to or during authentication, theendpoints 104 and 106 both sent a request to a STUN server (e.g., theSTUN server 214 of FIG. 2) (not shown in FIG. 22). The STUN serverdetermined an outbound IP address, an external port, and a type of NATfor the endpoints 104 and 106 (in this example, for the NAT devices 2204and 2206). The STUN server 214 then sent a STUN response back to theendpoints 104 and 106 with the collected information. The endpoints 104and 106 then sent an authentication request to an access server (e.g.,the access server 102 of FIG. 1) (not shown in FIG. 22). The requestcontains the information about endpoints 104 and 106 received from theSTUN server 214. The access server 102 responds to the requests bysending the relevant profile and routing table to the endpoints 104 and106. In addition, each NAT device 2204 and 2206 may have a pinhole tothe STUN server 214.

In the present example, the NAT device 2204 has an external address/portof 1.1.1.1:1111 and the NAT device 2206 has an external address/port of2.2.2.2:2222. The STUN server 214 has an address/port of 3.3.3.3:3333and the stateless reflector has an address/port of 4.4.4.4:4444. It isunderstood that the STUN server and/or stateless reflector 2202 may havemultiple addresses/ports.

Referring to FIG. 24 and with additional reference to FIG. 25, in step2402, the endpoint 104 sends a packet to the stateless reflector 2202.The packet contains header information identifying the source as theendpoint 104 (or rather, the external IP address of the NAT device 2204)and the destination as the stateless reflector 2202. The packet alsocontains custom or supplemental header information identifying thesource as the STUN server 214 and the destination as the endpoint 106.Accordingly, the IP/UDP header of the packet sent from the endpoint 104(via the NAT device 2204) identifies its source as 1.1.1.1:1111 and itsdestination as 4.4.4.4:4444.

In step 2404, the stateless reflector 2202 modifies the packet header byreplacing the IP/UDP header with the source and destination from thecustom header. In the present example, the stateless reflector 2202 willmodify the IP/UDP header to identify the packet's source as 3.3.3.3:3333and its destination as 2.2.2.2:2222. Identifying the packet's source asthe STUN server 214 enables the stateless reflector 2202 to send thepacket through the pinhole in the NAT device 2206 that was created whenthe endpoint 106 logged on. After modifying the header, the statelessreflector 2202 sends the packet to the endpoint 106 via the NAT device2206 in step 2406.

In step 2408, the endpoint 106 sends an acknowledgement (e.g., a 200 OK)directly to the endpoint 104. The address of the endpoint 104 iscontained within the payload of the packet. The endpoint 106 is able tosend the acknowledgement directly because the NAT device 2204 is eithera no NAT or a full cone type. Because the endpoint 106 has opened apinhole through the restricted or port restricted NAT device 2206 to theendpoint 104 by sending a message to the endpoint 104, the endpoint 104is now able to communicate directly with the endpoint 106, as indicatedby step 2410.

Referring again to table 2300 of FIG. 23, if the originating NAT type iseither a no NAT type or a full cone type, then the originating NAT canestablish communications with a terminating NAT type that is symmetriconly after using the stateless reflector 2202 to reflect a packet andthen performing a port capture. This process is described below withrespect to FIG. 26.

Referring to FIG. 26, steps 2602, 2604, 2606, and 2608 are similar tothe reflection process described with respect to FIG. 24, and will notbe described in detail in the present example. Because the terminatingNAT type is symmetric, the originating NAT needs the port of theterminating NAT in order to send packets through the NAT device 2206.Accordingly, in step 2610, the endpoint 104 will capture the externalport used by the NAT device 2206 to send the acknowledgement in step2608. This port, along with the address of the NAT device 2206, may thenbe used when communicating with the endpoint 106, as indicated by step2612.

Referring again to table 2300 of FIG. 23, if the originating NAT type iseither a restricted cone type or a port restricted cone type, then theoriginating NAT can establish communications with a terminating NAT typethat is either restricted or port restricted by using a fake packet andthen using the stateless reflector 2202 to reflect a packet. Thisprocess is described below with respect to FIG. 27.

Referring to FIG. 27, in step 2702, the endpoint 104 sends a fake packetto the endpoint 106. Because the originating NAT type is a restrictedcone type or a port restricted cone type, the fake packet opens apinhole to the terminating NAT that will allow a response from theterminating NAT to penetrate the originating NAT. After sending the fakepacket, the sequence 2700 proceeds with steps 2704, 2706, 2708, and2710, which are similar to the reflection process described with respectto FIG. 24, and will not be described in detail in the present example.The endpoints 104 and 106 may then communicate directly, as indicated bystep 2712.

Referring again to table 2300 of FIG. 23, if the originating NAT type isa symmetric type, then the originating NAT can establish communicationswith a terminating NAT type that is either no NAT or full cone after aport capture occurs. This process is described below with respect toFIG. 28.

Referring to FIG. 28, in step 2802, the endpoint 104 (symmetric NATtype) sends a message to the endpoint 106. In step 2804, the endpoint106 captures the external port used by the NAT device 2204 in sendingthe message. This port, along with the address of the NAT device 2204,may then be used when communicating with the endpoint 104 directly, asindicated by step 2806.

Referring again to table 2300 of FIG. 23, if the originating NAT type isa restricted cone type, then the originating NAT can establishcommunications with a terminating NAT type that is symmetric by using afake packet, reflecting a packet using the stateless reflector 2202, andthen performing a port capture. This process is described below withrespect to FIG. 29.

Referring to FIG. 29, in step 2902, the endpoint 104 sends a fake packetto the endpoint 106. Because the originating NAT type is a restrictedcone type, the fake packet opens a pinhole to the terminating NAT thatwill allow a response from the terminating NAT to penetrate theoriginating NAT. After sending the fake packet, the sequence 2900proceeds with steps 2904, 2906, 2908, and 2910, which are similar to thereflection process described with respect to FIG. 24, and will not bedescribed in detail in the present example. In step 2912, the endpoint104 captures the external port used by the NAT device 2206 in sendingthe acknowledgement in step 2910. This port, along with the address ofthe NAT device 2206, may then be used when communicating with theendpoint 106 directly, as indicated by step 2914.

Referring again to table 2300 of FIG. 23, if the originating NAT type isa symmetric type, then the originating NAT can establish communicationswith a terminating NAT type that is a restricted cone type by using areflect, a fake packet, and a port capture. This process is describedbelow with respect to FIG. 30.

Referring to FIG. 30, steps 3002, 3004, and 3006 are similar to thereflection process described with respect to FIG. 24, and will not bedescribed in detail in the present example. In step 3008, in response tothe reflected message from the endpoint 104, the endpoint 106 sends afake packet to the endpoint 104. Because the terminating NAT type is arestricted cone type, the fake packet opens a pinhole to the endpoint104 to allow messages from the endpoint 104 to traverse the NAT device2206. Accordingly, in step 3010, the endpoint 104 can send the nextmessage directly to the endpoint 106 through the pinhole. In step 3012,the endpoint 106 captures the external port used by the NAT device 2204to send the message in step 3010. This port, along with the address ofthe NAT device 2204, may then be used by the endpoint 106 whencommunicating directly with the endpoint 104, as indicated by step 3014.

Referring again to table 2300 of FIG. 23, if the originating NAT type isa symmetric type and the terminating NAT type is a port restricted cone,or if the originating NAT type is a port restricted cone and theterminating NAT type is symmetric, then all signaling between the twoNAT devices is relayed via the stateless reflector 2202, while media istransferred via peer-to-peer, as described previously. If both theoriginating and terminating NAT types are symmetric, then all signalingand media are relayed via the stateless reflector 2202.

Accordingly, the peer-to-peer communications described herein may beachieved regardless of the NAT type that may be used by an endpoint. Thestateless reflector 2202 need not know the information for each client,but instead reflects various packets based on information containedwithin the packet that is to be reflected. Both the custom header andpayload may be encrypted for security purposes. However, the statelessreflector 2202 may only be able to decrypt the custom header and thepayload itself may only be decrypted by the terminating endpoint. Thisenables the stateless reflector 2202 to perform the reflectionfunctionality while maintaining the security of the payload itself. Asdescribed above, not all processes for traversing a NAT device may usethe stateless reflector 2202.

While the preceding description shows and describes one or moreembodiments, it will be understood by those skilled in the art thatvarious changes in form and detail may be made therein without departingfrom the spirit and scope of the present disclosure. For example,various steps illustrated within a particular sequence diagram may becombined or further divided. In addition, steps described in one diagrammay be incorporated into another diagram. For example, the STUNrequest/response steps of FIG. 5 may be incorporated into diagrams thatdo not show this process. Furthermore, the described functionality maybe provided by hardware and/or software, and may be distributed orcombined into a single platform. Additionally, functionality describedin a particular example may be achieved in a manner different than thatillustrated, but is still encompassed within the present disclosure.Therefore, the claims should be interpreted in a broad manner,consistent with the present disclosure.

1. A method for enabling a first endpoint to traverse a network addresstranslation (NAT) device associated with a second endpoint in apeer-to-peer communications system, wherein the NAT device includes apinhole maintained between the NAT device and a server, the methodcomprising: determining whether a message sent to the second endpointfrom an external source will only pass through the NAT device if thesecond endpoint has first sent a message to the external source; if thedetermining indicates that the second endpoint must first send amessage, sending a first message to a stateless reflector for reflectionto the second endpoint, wherein the first message includes a messageheader identifying the stateless reflector as the message destinationand the first endpoint as the message source; modifying the messageheader by the stateless reflector, wherein the modifying inserts thesecond endpoint as the message destination and the server as the messagesource; and sending the modified first message to the second endpointvia the pinhole in the NAT device.